Rafael Benítez said he had no problems with the squabble that erupted between David Luiz and Frank Lampard as the teams departed at half-time, pointing to the tête-a-tête as recognition of a need to improve. Chelsea eventually forced their way into the Europa League semi-finals 5-4 on aggregate despite a sloppy 3-2 defeat by Rubin Kazan.

David Luiz and Lampard became embroiled in an argument in the middle of the pitch as they retreated towards the changing rooms; the finger-jabbing continuing until they approached the tunnel, where Petr Cech and Yossi Benayoun shepherded them away from each other.

The disagreement came in the stadium where Blackburn Rovers' David Batty and Graeme Le Saux famously fought one another in 1995. On this occasion, the frustration appeared to be born of a chance conceded to Gokdeniz Karadeniz just before the whistle, which Cech had pushed to safety, with Lampard initially unhappy at the ease with which the Russian club had created the opportunity.

The visitors were hardly defensively sound over the remainder of the tie, with Rubin scoring three – albeit one a soft penalty after Aleksandr Ryazantsev's dive – and clipping a post, though Benítez put the vulnerability down to playing in an arena with 65,000 empty seats. "It's always good to have players arguing about things that happen on the pitch so you can correct these things at half-time," he said. "We were talking about that, adjusting positions, so it's fine. Not a problem."

The Spaniard singled out the little-used Paulo Ferreira and Nathan Ake for praise, despite both enduring awkward evenings. "You have to put all this into context," he said. "We came here to play on a synthetic pitch which, although it's the same for both sides, is not ideal; [Ryan] Bertrand couldn't come so we had to play Paulo, who'd not played for a while, at left-back; and we have another game on Sunday, another big semi-final [in the FA Cup], so to score twice and go through makes us really pleased. Yes, we're disappointed we didn't defend well in the second half, but still we go through.

"The timing of the goals made it harder. Our first made a big difference in the tie and made us confident: not over-confident, but when they scored we had to start again. The same with our second goal: the game felt finished but it wasn't. We had to work hard again. We had to deal much better with the crosses, something we couldn't do, but credit to all our players. Despite the circumstances, we're in another semi-final."

That will be the 18th of the Roman Abramovich era and maintains Chelsea's pursuit of a trophy despite a trying and draining campaign. Lampard said: "People try and talk this competition down but we have been very professional and the closer you get to the final, the more special it gets. We have to get home and concentrate on the FA Cup now. We have a lot of games coming up but have big squad so today is a confidence booster. We're into a semi-final, now we want to get into a final."

Benítez added: "In terms of this season, it's another semi-final. We've played a final [in the Fifa Club World Cup], another semi-final [in the Capital One Cup], and we're in two more semi-finals. I know we are disappointed with some of the defending in the second half here, but this game has to be put into proper context. It was a different kind of environment, but I think we did well."